Fat requirement of Bester in winter feeding; effect of fat levels on growth indices and body chemical composition

This study aimed to determine the fat requirement and effect of dietary fat levels on growth and body composition indices of Bester (Huso huso ♀ × Acipenser ruthenus ♂) juveniles( 200.3 ± 2 g) in winter feeding. Fish were fed by 5 isonitrogenous diets (40% crude protein) with different fat levels including 10, 13, 16, 19 and 22%, 3 times daily according to the satiation for 50 days. The results showed that some growth indices such as final weight, body weight increase, specific growth rate, feed conversion ratio and protein efficiency ratio were significantly affected by different levels of dietary fat. Proximate analysis indicated that the fat, moisture and protein contents of the whole body were affected by the diets, body composition of fish fed the 22% fat diet showed significantly higher fat and lower moisture contents, as well as body composition of fish, fed 10% fat in the diet showed significantly higher moisture lower protein and lower fat. From the results, the present study suggests that more suitable dietary fat levels in winter feeding for the Bester growth might be around 13%.